The present disclosure relates to image forming apparatuses, such as electrographic copiers, printers, and facsimile machines, as well as multifunction peripherals combining their functions.
Recent years, amorphous silicon (a-Si) photosensitive drums have been widely used as an image bearing member for an image forming apparatus utilizing an electrographic process. An a-Si photosensitive drum has high hardness and excellent durability, and its characteristics as a photosensitive member are substantially without degradation even after a prolonged usage. Therefore, high image quality can be maintained. That is to say, an a-Si photosensitive drum is an excellent image bearing member for its low running cost, easy handling characteristics, and high level of safety to the environment.
An image forming apparatus using such an a-Si photosensitive drum is known to involve a greater risk of image deletion owing to the characteristics of the a-Si photosensitive member. Image deletion refers to a phenomenon in which an image is blurred or smudged. Image deletion occurs when ion products adhere to the surface of the photosensitive drum and the ion products absorb moisture from the atmosphere. In particular, when the surface of the photosensitive drum is charged by a charging unit, nitrogen oxide (NOx) adheres to the surface of the photosensitive drum. The nitrogen oxide absorbs moisture, causing the latent charges to flow along the surface on which the latent image is formed. As a result, image deletion occurs in the electrostatic latent image formed on the surface of the photosensitive drum. Image deletion tends to occur especially at the edge portions of an electrostatic latent image.
Various methods have been suggested to reduce occurrence of image deletion. In one example, a heating element (heater) is provided inside the photosensitive drum, and a hygrothermograph sensor is provided inside the image forming apparatus. The heating element is heated based on the temperature and humidity measured by the hygrothermograph sensor. With this arrangement, even if moisture adheres to the surface of the photosensitive drum, the moisture can be evaporated. Consequently, occurrence of image deletion can be prevented.
Unfortunately, in the case where the heater is provided inside the photosensitive drum, a sliding electrode is required to connect the heater and the power supply. Therefore, there is a sliding portion connecting the heater to the power supply. As the total rotation time of the photosensitive drum is prolonged, connection failure may occur at the sliding portion.
In view of the above, a suggestion is made to provide the heating element in a static eliminating section. In particular, the static eliminating section includes a substrate, a light-emitting element, and a heating element. The light-emitting element is attached to one main surface of the substrate and emits light toward the photosensitive drum. The light emission by the light-emitting element eliminates the charges on the photosensitive drum. The heating element is disposed on the other main surface of the substrate. The heating element heats the photosensitive drum.